Residue tolerance limits

The maximum permitted residues in different crops are legal limits for specific compounds on and in specific foods. They are calculated from ADI values, taking into account the amount of the specific food that is likely to 

Pesticide Rat Oral LD50 (mg/kg) Toxicity Class (WHO) ADI (mg/kg of body weight) 

Source The data are taken from Tomlin, C., Ed. 2000. The Pesticide Man-mi A World Compendium. British Crop Protection Council, Farnham, Surrey. 1250 pp. 

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Application of IP and NCS in conjunction with specification tolerance limits enables to substantiate acceptance criteria for linear regression metrological characteristics (residual standard deviation, correlation coefficient, y-intercept), accuracy and repeatability. Acceptance criteria for impurity influence (in spectrophotometric assay), solution stability and intermediate precision are substantiated as well. 

Example 31 In Table 2.5, the term under the root would increase from 0.264 to 1.264 this increase by a factor of 4.8 translates into CI( y) being 2.2 times larger than CI(T). The corresponding test at x = 125 (0.517 < y(x) < 0.547) shows the measured value in Table 2.2 (0.537) to be well within the tolerated limits. Only if the residual standard deviation (0.00363) was much larger than expected for the analytical method would there be reason to reassess this calculation. 

FFDCA, among other things, assured the safety of processed foods by establishing safe tolerance limits for pesticide residues in processed foods. The mles and interpretation of the mles were not always consistent between these two government offices. 

CMA), and the USDA are excellent sources of information relative to current regulatory activities which will impact both production agriculture and the setting of tolerances to ensure food safety. The purpose of this article is to summarize the key impacts of the 1996 OPPTS 860 Residue Chemistry Test Guideline series as they impact research associated with field production of RAC samples to be used in establishing safe tolerance limits for pesticides used in commercial agricultural production. 

Food Chain Bioaccumulation. Diazinon has an estimated low bioconcentration potential (BCF=77) (Kenaga 1980) in aquatic organisms, which is generally confirmed by measured BCF values obtained from laboratory studies with fish and other aquatic invertebrates (El Arab et al. 1990 Keizer et al. 1991 Sancho et al. 1993 Tsuda et al. 1989, 1995). Further information on measured BCF values for additional edible fish and shellfish would be helpful, as would information on tissue residues of diazinon and its major degradation products in edible species. No information was found on studies associated with plant uptake, but diazinon is rarely detected above EPA tolerance limits (Hundley et al. 1988). Bioaccumulation in aquatic food chains does not appear to be important, and no further information on biomagnification is required. 

The EPA has established a tolerance limit of 0.1 ppm for residues of aluminum phosphide in or on raw agricultural commodities such as almonds, barley, com, dates, rice, sesame seeds, and wheat when it is used as a post-harvest treatment (EPA 1977b). 

The residual variance after fitting the model can be used to compute tolerance limits around the model. This is illustrated by cylinders in Fig. 11. For obtaining reliable predictions with new objects, these should be within the the tolerance limits in the X space. 

It is well known that mans food may contain residues of various types of pesticides which may actually approach the legal tolerance limit or are significantly below it. However, as stated by Crosby (9), under practical conditions, a significant proportion of the pesticide applied directly to food crops is immediately lost to the environment such as to... 

Tolerance The amount of a chemical substance legally permitted in food products tolerance limits are established through formal regulatory procedures—for instance, permissible residue levels for pesticides in raw agricultural produce and processed foods. The use of products with no indication of tolerance values is considered illegal... 

Fig. 3 Determination of the withdrawal time from the 95% confidence bound on the 99% statistical tolerance limit on the residue depletion data rounded to the next day. (From Ref., reprinted with permission from Dairy, Food and Environmental sanitation. Copyright held by the International Association for Food protection.)...

Tolerance limits for solvents residues in spice oleoresins are given in Regulation 36-3 (h) ... 

A seven year study by the Indian Council of Medical Research released in 1993 analysed 2205 cow and buffalo milk samples from 12 states. HCH (lindane) was detected in about 85% of the samples, with up to 41% of the samples exceeding tolerance limits. DDT residues were detected in 82% of the samples and 37% contained residues above the limit of 0.05 mg/kg, in some cases 44 times higher at 2.2 mg/kg. 

In contrast, the EU approach consists of computing a TMDI using MRL, not median residue concentrations CVMP criticized the JECFA approach for its intrinsic limitation to a chronic risk scenario and also for several technical reasons, including difficulties of using linear regression to estimate the tolerance limit of residue concentrations with its confidence interval and to the rather loose concept of good veterinary practice. (For further details, see Ref. 106. For further details on and a discussion of the USFDA approach, see Refs. 105 and 108.)... 

The second and preferred method is to apply appropriate statistical analysis to the dataset, based on linear regression. Both EU and USFDA authorities assume log-linear decline of residue concentrations and apply least-squares regression to derive the fitted depletion line. Then the one-sided upper tolerance limit (95% in EU and 99% in USA) with a 95% confidence level is computed. The WhT is the time when this upper one-sided 95% tolerance limit for the residue is below the MRL with 95% confidence. In other words, this definition of the WhT says that at least 95% of the population in EU (or 99% in USA) is covered in an average of 95% of cases. It should be stressed that the nominal statistical risk that is fixed by regulatory authorities should be viewed as a statistical protection of farmers who actually observe the WhT and not a supplementary safety factor to protect the consumer even if consumers indirectly benefit from this rather conservative statistical approach. 

There are differences between regulatory authorities in procedures used to set milk withholding periods. USFDA/CVM requires use of at least 20 animals and analysis of milk samples for the marker residue in triplicate.If the product is authorized for mastitis treatment, it is assumed that no more than one-third of the milk is derived from treated cows. A regression line is fitted to the log residue concentration data for each cow, and then fitted lines are used to estimate the distribution of log residue concentrations at each sampling time. Between-animal variance and measurement error variability are estimated and used to calculate a tolerance limit at each time. The WhT is set as the first time at which the upper 95% confidence limit of the 99th percentile of residue concentrations is equal to or less than the MRL. 

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